黄铁矿对煤生物产气和微生物群落结构的影响

Influence of pyrite on biogenic coal bed methane production and microbial community structure

摘要:

【目的】研究煤中矿物质黄铁矿对生物产气的影响。【方法】本研究以陕西榆林煤作为生物产气底物，以实验室前期驯化的产甲烷微生物作为出发菌群，通过在厌氧体系中添加不同质量的黄铁矿进行煤生物模拟产气试验。利用气相色谱仪、液相色谱仪、酶标仪、傅里叶红外光谱仪和Illumina高通量测序平台研究产气过程中CH₄含量、总挥发性脂肪酸(volatile fatty acids, VFAs) 浓度、辅酶F₄₂₀含量、产气前后煤中有机官能团和微生物群落结构的变化。【结果】添加适量黄铁矿在产气前期(15-22 d)能促进CH₄生成，而产气后期(29-50 d)会抑制产气，而且添加0.5%黄铁矿的在前中期的产气量比对照组高48.1%，累计产气量达到193.67 μmol/g-coal。生物产气实验组反应液中的VFAs和辅酶F₄₂₀浓度整体均高于对照组，说明添加黄铁矿促进了反应体系中产酸细菌和产甲烷菌的活性。添加黄铁矿后煤中的醇和酚羟基，-NH-和-NH₂更易被微生物利用。黄铁矿添加对细菌和古菌的群落多样性有影响，其中古菌影响较大。添加少量黄铁矿可以提升拟杆菌门(Bacteroidota)的群落丰度，而添加黄铁矿较多时可以提升细菌中的芽孢杆菌门(Bacillota)的群落丰度。黄铁矿对体系中的嗜蛋白菌属(Proteiniphilum)、硫还原菌属(Desulfurella)和JGI-0000079-D21细菌影响最为显著。添加黄铁矿后，古菌中的海拉古菌门(Halobacterota)和甲烷八叠球菌属(Methanosarcina)丰度变化较大，黄铁矿对体系中的产甲烷古菌属Methanosarcina、Methanomassiliicoccus和Methanobacterium影响最为显著。【结论】添加少量黄铁矿会对煤的生物产气具有促进作用，同时会影响发酵过程中微生物群落的组成。

Abstract:

[Objective] To investigate the coal’s pyrite on the biological gas production. [Methods] In present work, we took the coal obtained from Yulin City, Shaanxi Province as substrate and the methanogenic microorganisms domesticated by our laboratory as inoculation flora. The simulation biological gas production of coal was carried out by dosing different content of pyrite into the anaerobic system. The changes of CH₄ content, total volatile fatty acids (VFAs) concentration, coenzyme F₄₂₀ content, organic functional groups of coal before and after gas production and microbial community structure were investigated by gas chromatograph, liquid chromatograph, microplate reader, Fourier infrared spectrometer and Illumina high-throughput sequencing platform. [Results] The addition of pyrite could promote the production of CH₄ in the early stage of gas production (15-22 d), while inhibited the production of CH₄ in the late stage (29-50 d). The gas production of 0.5% dosage pyrite in the early and middle stages was 48.1% higher than that of the control group, and the cumulative gas production reached 193.67 μmol/g-coal. The concentrations of VFAs and coenzyme F₄₂₀ in the experimental group were higher than those in the control group, indicating that the addition of pyrite promoted the activities of acid bacteria and methanogens in the reaction system. After adding pyrite, alcohol and phenol hydroxyl, -NH- and -NH₂ in coal were more easily utilized by microorganisms. Adding pyrite could influence the community diversity of bacteria and archaea, and greater effect on the latter. Adding a small amount of pyrite could improve the community abundance of Bacteroidota, while more pyrite could increase the community abundance of Bacillota. Pyrite had the most significant impact on Proteiniphilum, Desulfurella and JGI-0000079-D21 bacteria in the system. After addition of pyrite, the abundance of Halobacterota and Methanosarcina changed greatly. Pyrite had the most significant effect on Methanosarcina, Methanomassiliicoccus and Methanobacterium. [Conclusion] A small amount of pyrite can promote the biological gas production of coal, and affect the microbial community structure in fermentation liquid.